Lumbar spinal fusion is commonly performed in humans but the failure rate of bone union is reported to range from 5-36%. Recently, osteoinductive growth factors synthesized by recombinant DNA technology have been shown to induce bone formation in heterotopic sites. Recombinant human BMP-2 (rhBMP-2) has been effective in generating spine fusions in a rabbit model. To determine the appropriate dose of the growth factor for human use and to determine the speed of healing, a non-human primate model has been chosen. Higher doses than expected were required to make bone in the primate, but it was successful. The growth factor was successfully delivered inside a hollow titanium threaded fusion cage through a minimally invasive approach. Studies in 1997 focused on fine tuning the necessary dose and studying alternative carrier materials for the growth factor including different combinations of ceramic materials. Studies in 1998 will focus on continuing to explore alternat ive carrier materials that will better bind the growth factor and still be resorbable. These studies are critical to providing the information needed for the next step which is human clinical trials. This treatment, if successful, will significantly impact on the care of spine patients and prevent multiple surgeries in the 5-35% of patients who do not heal their spine fusion on the first attempt.